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Hygroscopicity measurement of sodium carbonate,β-alanine and internally mixed β-alanine/na2CO3 particles by ATR-FTIR

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Journal of Environmental Sciences 2020年第1期32卷 250-259页

作者： Ping Yang Hui Yang na wang Chunyun Du Shufeng Pang Yunhong Zhang School of Chemistry and Chemical Engineering Beijing Institute of Technology

Water-uptakes of pure sodium carbonate(na2CO3),pureβ-alanine and internally mixedβ-alanine/na2CO3 aerosol particles with different mole ratios are first monitored using attenuated total reflectance Fourier transform infrared spectroscopy(ATR-FTIR)*** pure na2CO3 aerosol particles,combining the absorptions at 877 and 1422 cm-1 with abrupt water loss shows the efflorescence relative humidity(ERH)of 62.9%–51.9%.Upon humidifying,solid na2CO3 firstly absorbs water to from na2CO3·H2O crystal at 72.0%RH and then deliquesces at 84.5%RH(DRH).As for pureβ-alanine particles,the crystallization takes place in the range of 42.4%–33.2%RH and becomes droplets at^88.2%***β-alanine is mixed with na2CO3 at various mole ratios,it shows no efflorescence of na2CO3 whenβ-alanine to na2CO3 mole ratio(OIR)is 2:*** 1:1 and 1:2β-alanine/na2CO3 aerosols,the ERHs of na2CO3 are 51.8%–42.3%and 57.1%–42.3%,***β-alanine crystal appears from 62.7%RH for 2:1 and 59.4%RH for both 1:1 and 1:2 particles and lasts to driest *** hydration,the DRH is 44.7%–75.2%for na2CO3 with the OIR of 1:1 and 44.7%–69.0%for 1:2 mixture,and those of β-alanine are 74.8% for 2:1 mixture and 68.9%for two *** the first dehumidification–humidification,all the water contents decrease despite of constituent *** at^92%RH,the remaining water contents are 92%,89%and 82%at^92%RH,corresponding to OIR of 2:1,1:1 and 1:2 mixed system,respectively.

关键词： Sodium carbonate β-Alanine Hygroscopicity Crystallization Immune effects Deliquescence

Existence of periodic solutions for the nonlinear functional differential equation in the lossless transmission line model

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Chinese Physics B 2012年第1期21卷 24-28页

作者： wang na Department of Mathematics East China Normal UniversityShanghai 200241China

We study a time delay equation for the lossless transmission line model. Under suitable conditions, by using the continuation theorem of the coincidence degree theory, the existence of the periodic solution for the no... 详细信息

关键词： periodic solution time delay nonlinearity coincidence degree

AnaLYSIS OF A FULLY DISCRETE FINITE ELEMENT METHOD FOR PARABOLIC INTERFACE PROBLEMS WITH NONSMOOTH INITIAL DATA

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Journal of Computational Mathematics 2022年第5期40卷 777-793页

作者： Kai wang na wang Department of Mathematics Southern University of Science and TechnologyShenzhen 518005China Applied and Computational Mathematics Division Beijing Computational Science Research CenterBeijing 100193China

This article concerns numerical approximation of a parabolic interface problem with general L 2 initial *** problem is discretized by a finite element method with a quasi-uniform triangulation of the domain fitting the interface,with piecewise linear approximation to the *** semi-discrete finite element problem is furthermore discretized in time by the k-step backward difference formula with k=1,...,*** maintain high-order convergence in time for possibly nonsmooth L 2 initial value,we modify the standard backward difference formula at the first k−1 time levels by using a method recently developed for fractional evolution *** error bound of O(t−k nτk+t−1 n h 2|log h|)is established for the fully discrete finite element method for general L 2 initial data.

关键词： Parabolic interface problem Finite element method Backward difference formulae Error estimate Nonsmooth initial data.

Entire Solution of the Degenerate Fisher Equation

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Acta Mathematicae Applicatae Sinica 2017年第1期33卷 75-82页

作者： Li-na wang School of Science Beijing Technology and Business University Beijing 100048 China

This paper deals with the solutions defined for all time of the degenerate Fisher equation. Some solutions are obtained by considering two traveling fronts with critical speed that come from both sides of the X-axis and mix. Unfortunately, the entire solutions which behave as two opposite wave fronts with non-critical speed approaching each other from both sides of the X-axis can not be obtained, because the essential difficulty originates from the algebraic decay rate of the fronts with non-critical speed.

关键词： entire solution degenerate Fisher traveling front

Time-dependent Vibration Frequency Reliability Analysis of Blade Vibration of Compressor Wheel of Turbocharger for Vehicle Application

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Chinese Journal of Mechanical Engineering 2014年第1期27卷 205-210页

作者： wang Zheng wang Zengquan ZHUANG Li wang A-na Science and Technology on Diesel Engine Turbocharging Laboratory China North Engine Research Institute Center of Engine Test and Measurement China North Engine Research Institute

Blade vibration failure is one of the main failure modes of compressor wheel of turbocharger for vehicle application. The existing models for evaluating the reliability of blade vibration of compressor wheel are static, and can not reflect the relationship between the reliability of compressor wheel with blade vibration failure mode and the life parameter. For the blade vibration failure mode of compressor wheel of turbocharger, the reliability evaluation method is studied. Taking a compressor wheel of turbocharger for vehicle application as an example, the blade vibration characteristics and how they change with the operating parameters of turbocharger are analyzed. The failure criterion for blade vibration mode of compressor wheel is built with the Campbell diagram, and taking the effect of the dispersity of blade natural vibration frequency and randomness of turbocharger operating speed into account, time-dependent reliability models of compressor wheel with blade vibration failure mode are derived, which embody the parameters of blade natural vibration frequency, turbocharger operating speed, the blade number of compressor wheel, life index and minimum number of resonance, etc. Finally, the rule governing the reliability and failure rate of compressor wheel and the method for determining the reliable life of compressor with blade vibration is presented. A method is proposed to evaluate the reliability of compressor wheel with blade vibration failure mode time-dependently.

关键词： turbocharger compressor wheel blade vibration reliability failure rate reliable life

Synthesis,Electrical Conductivity and Seebeck Coefficient of La_(0.9)A_(0.1)FeO_3(A=Mg,Ca,Sr,Ba)

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Journal of Materials Science & Technology 2010年第12期26卷 1103-1106页

作者： na Yin Hongchao wang Chunlei wang School of Physics State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China

Lanthanum ferrites ceramics La0.9A0.1FeO3 （A=Mg, Ca, Sr, Ba） have been prepared by solid state reaction. X-ray power diffraction analysis reveals that all samples are of pure perovskite structure with orthorhombic phase. Electrical conductivity and Seebeck coefficient have been measured in vacuum within the temperature range between room temperature and 800℃. The electrical conductivity shows semiconducting behavior. Temperature dependence of electrical conductivity indicates that adiabatic small-polaron hopping mechanism is dominant for their electric transportations. Seebeck coefficients are positive for samples, suggesting ptype conduction in the whole temperature range. The highest Seebeck coefficient is found to be 654 μV/K for La0.9A0.1FeO3. Except La0.9A0.1FeO3, the electrical conductivity of La0.9A0.1FeO3 increases with increasing atomic number of the A-site element, while Seebeck coefficient decreases.

关键词： La0.9A0.1FeO3 ceramics Electrical conductivity Seebeck coefficient

Characterization and evaluation of UV-irradiation aging of urushi by micro-UV/Py-GC/MS system

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Science China(Technological Sciences) 2023年第8期66卷 2258-2270页

作者： wang na GU An LEI Yong Department of Conservation Science The Palace MuseumBeijing 100009China

Lacquer is the main raw material of lacquerware,while UV-irradiation is an important factor leading to its *** order to investigate the aging behavior of urushi lacquer film under UV-irradiation,and to propose parameters that can be used to evaluate its aging degree,the micro-UV/Py-GC/MS system has been applied in the present work to enrich and identify volatile products released by urushi film during aging on the one hand,and to investigate micro-amount and conventional urushi films with different aging degrees on the other hand,in addition,representative historical samples have also been *** products released by urushi film demonstrate that during UV-irradiation,polysaccharides wrapping urushiol polymer would be first degraded to generate furans and alcohols,and then urushiol polymer would undergo photo-oxidation and break of molecular chain,mainly generating oxidation products including aldehydes,organic acids,and ketones,as well as a small number of alkyl benzenes and ***-GC/MS analysis of micro-amount urushi films with different aging degrees indicates that UVirradiation is more destructive to aliphatic chains in urushiol polymer,but it also can accelerate the polymerization of microamount urushi ***-GC/MS analysis of conventional urushi films indicates that with the increase of aging degree,the total chromatographic peak area ratio of hydrocarbons to benzene derivatives gradually increases,the peak area ratio of 3-pentadecenyl-catechol to 3-pentadecyl-catechol gradually decreases,and the peak area ratio of aging products of urushiol to 3-pentadecyl-catechol gradually *** above parameters were further used to evaluate the aging degree of two urushicontained samples separately collected from the surface and interior of a carved lacquer panel in the Forbidden City,and evaluation results are in accord with the natural aging law and further verify the reliability of the proposed *** results of the pre

关键词： urushi UV-irradiation aging micro-UV/Py-GC/MS aging degree evaluation

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Multi-Attribute Preferences Mining Method for Group Users with the Process of Noise Reduction

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Journal of Computer Science & Technology 2021年第4期36卷 944-960页

作者： Qing-Mei Tan Xu-na wang College of Economic and Management Nanjing University of Aeronautics and AstronauticsNanjing 211106China Research Base for Civilian-Military Integration Development in Jiangsu Province Nanjing 211106China

Traditional researches on user preferences mining mainly explore the user’s overall preferences on the project,but ignore that the fundamental motivation of user preferences comes from their attitudes on some attributes of the *** addition,traditional researches seldom consider the typical preferences combination of group users,which may have influence on the personalized service for group *** solve this problem,a method with noise reduction for group user preferences mining is proposed,which focuses on mining the multi-attribute preference tendency of group ***,both the availability of data and the noise interference on preferences mining are considered in the algorithm *** the process of generating group user preferences,a new path is used to generate preference keywords so as to reduce the noise ***,the Gibbs sampling algorithm is used to estimate the parameters of the ***,using the user comment data of several online shopping websites as experimental objects,the method is used to mine the multi-attribute preferences of different *** proposed method is compared with other methods from three aspects of predictive ability,preference mining ability and preference topic *** results show that the method is significantly better thap other existing methods.

关键词： preferences mining group user multi-attribute noise reduction noise interference

Coset Structure of Spin Group

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Communications in Theoretical Physics 2007年第6期47卷 987-994页

作者： wang na WU Ke School of Mathematical Science Capital Normal University Beijing 100037 China Key Laboratory of Mathematics Mechanization The Chinese Academy of Sciences Beijing 100080 China

This article considers One example is also given to take a the coset structure closer look at what of spin group via analyzing the expression of its representation. the coset and the subgroup are.

关键词： spin group group representation coset structure